1 of WHP-San Francisco, serves as Director of the Gladstone Institute of Virology and Immunology. 16. LETTERS OF SUPPORT (e.g., Consultants) Letters of support from the following consults are included on pages 79-83. Beatrice Hahn, MD / George Shaw, MD, PhD (University of Alabama, Birmingham) will provide their technical assistance and advice regarding methods to amplify, sequence and clone the envelope genes from HIV-1 virions from newly infected women and their transmitting male partner identified in the OPTIONS cohort. Specifically, they will assist in single genome amplification, a technique that precludes in vitro recombination during the PCR reaction. Dr. Shaw is a member of the CHAVI Scientific Leadership group and Program Leader of the CHAVI HIV Virus Biology Discovery Team while Dr. Hahn directs the Viral Sequencing Core in the Center for HIV/AIDS Vaccine Immunology (CHAVI). Barton F. Haynes, MD (Duke University, Durham, North Carolina) is the Director of CHAVI and has formally approved our collaborative efforts with Drs. Beatrice Hahn and George Shaw at the University of Alabama. In the future, we may elect to use envelopes isolated during acute infection in CHAVI when matched M->F transmission pairs are formally identified. Support for these studies is indicated in Dr. Haynes letter. Frederick Hecht, MD (University of California, San Francisco) also forms a key collaborator regarding Specific Aim 1. He will provide the serum samples and semen from M^-F transmission pairs from the OPTIONS (acute infection) cohort. He is currently recruiting more transmission pairs identified as part of the OPTIONS